In recent years, an electronic key system, such as a smart entry system, has a portable wireless key to perform a control pertaining to locking and unlocking of a vehicle door lock. Such a portable wireless key is carried by a person like a mobile phone, and thus requires durability in dropping. Further, metal decoration members made of zinc die-casting have been widely used in portable wireless keys in order to improve design (decoration). In this case, the weight increases as compared to a conventional resin component. Therefore, a holding structure satisfying the durability in dropping is largely required. As a result, a fixing structure of the metal decoration member is complicated, and a workability in assembling increases. In addition, a component to make the holding structure for the durability in dropping is necessary, resulting in increases in the number of components and costs. In the portable wireless keys, the number of switches (operation portions) is different depending on vehicles, and designs according to the number of switches are necessary. Even when the number of the switches is the same, functions and arrangements are different. Thus, a large number of switch variations exist. To address the switch variation, for example, a patent literature 1 describes to make case components for respective switches. In such a case, however, initial costs increase.